Cigarette packaging machines now operate at such high output rates as to require large amounts of packaging material, which is partly supplied in the form of strips wound into reels. Each reel comprises a strip of packaging material wound about a spool having a central hole, and is fitted onto an unwinding pin on the packaging machine. The strip of packaging material is unwound off the reel, and sheets of packaging material are cut off the strip and folded about groups of cigarettes.
The increase in the amount of packaging material required calls for automatic reel handling to speed up reel feed to the machine, which in turn calls for determining the position of the reel to enable a reel manipulator to grip the reel by means of a gripping member and align the reel with an unwinding pin on the packaging machine.
Patent EP-A-551,854 relates to a manipulator featuring a reel gripping member and for picking reels off a pallet on which the reels are arranged with their respective axes positioned vertically. The gripping member has a TV camera for picking up an image of a reel; and an arithmetic unit for processing the image data by means of an algorithm based on translation and inversion of the image to determine the coordinates of a characteristic point on the reel. Once the coordinates of the characteristic point on the reel are determined, the manipulator sets the gripping member to a given position to grip the reel correctly.
Though reliable and capable of transferring a large number of reels per unit of time, the arithmetic unit of the above manipulator for processing the points in the image is relatively expensive.